A hidden region in the third variable domain of HIV-1 IIIB gp120 identified by a monoclonal antibody
article
The third variable domain (V3 domain) of HIV-1 gp120 is involved in virus neutralization by antibody, in determination of cell tropism, and in syncytium-inducing/non-syncytium-inducing capacity. Antibodies are highly specific tools to delineate the role of different V3 amino acid sequences in these processes, and to dissect events occurring during synthesis of gp120/160, gp120-CD4 interaction, cellular infection, and syncytium formation. We describe here an IgG1 murine monoclonal antibody (MAb), coded IIIB-V3-01, that was raised with a synthetic peptide (FVTIGKIGNMRQAHC) derived from the carboxy-terminal flank of the HIV-1 IIIB V3 domain. The binding site of this antibody was mapped to the sequence IGKIGNMRQ, using Pepscan analysis. In ELISA, this antibody binds to E. coli-derived gp120 from HIV-1 IIIB, which is denatured and not glycosylated. The antibody showed no neutralizing activity against HIV-1 IIIB, MN, SF2, or RF in a virus neutralization assay and in a syncytium formation inhibition assay. In addition, this antibody did not react with gp120 expressed on the surface of IIIB-infected MOLT-3 cells in FACS analysis. To assess whether the epitope defined by MAb IIIB-V3-01 is hidden on native gp120, reactivity of the antibody with SDS-DTT-denatured or DTT-denatured glycosylated gp120 (CHO cell produced) was tested. Both these treatments exposed the epitope for binding. From these data we conclude that the epitope defined by MAb IIIB-V3-01 is hidden on glycosylated recombinant gp120, and is not accessible on gp120 expressed on the membrane of HIV-1, IIIB-infected cells. The results described contribute to the understanding of the three-dimensional structure of native gp120. Chemicals/CAS: Antibodies, Monoclonal; Binding Sites, Antibody; HIV Antibodies; HIV envelope protein gp120 (305-321); HIV Envelope Protein gp120; Peptide Fragments
Topics
epitopeglycoprotein gp 120immunoglobulin g antibodymonoclonal antibodyanimal cellantigen antibody reactionantigen bindingarticlebinding sitecell membranecontrolled studyfemalemousenonhumanprotein domainprotein structuresyncytiumvirus cell interactionvirus neutralizationAmino Acid SequenceAnimalAntibodies, MonoclonalBinding Sites, AntibodyFemaleGiant CellsHIV AntibodiesHIV Envelope Protein gp120HIV-1HumanMiceMice, Inbred BALB CMolecular Sequence DataNeutralization TestsPeptide FragmentsSupport, Non-U.S. Gov'tSupport, U.S. Gov't, P.H.S.
TNO Identifier
232154
ISSN
08892229
Source
AIDS Research and Human Retroviruses, 9(7), pp. 605-612.
Pages
605-612
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